Conveying liquids at high pressure by means of ejectors



March 21, 1933. w P. SCHMIDT 3 CONVEYING LIQUIDS AT HIGH FRESSURE BYMEANS OF EJECTORS Filed Aug. 14, 1930 Patented Mar. 21; 1933 UNITEDSTATES PATENT OFFICE PAUL SCHMIDT, OF MUNICH, GERMANY CONVEYING LIQUIDSAT HIGH PRESSURE BY MEANS EJ'ECTORS Application filed August 14, 1930,Serial No. 475,303, and in Germany August 21,1929.

Ejectors are, in general, only used for the production of reducedpressures, for example, for the draining oftrenches or cellars, for theemptying of vessels and the like, using water under pressure, is takenfrom the water mains. The height of delivery, in such cases amounts onlyto a few metres, whereas the driving pressure of the pressure liquidamounts to several atmospheres.

Experimental investigation of the pressures set up by ejector pumps forthe pro duction of high pressures it has now been found that hydraulicadvantages can be obtained by dividing the driving fluid up intoseparate streams and delivering these streams in succession to theflowing liquidto be delivered. The value from the hydraulic andcommercial standpoints of theimprovement obtained becomes moreparticularly manifest when the drivin pressure of the pressure liquidamounts on y to a fractional part of the total height to which theliquid to be delivered israised. By driving pressure as that term isused in connection with the present in-' vention, is meant the workingpressure, or head that is to say, the difference of pressure between theinlet and outlet of the pressure liquid to and from the machine.

The invention, therefore, relates to the delivery of a liquid at highpressure by means of ejectors and its subject matter consists insubdividing the driving liquid into separate streams and deliveringthese streams 1n succession to the flowing liquid to be delivered.

For low delivery heights the use of an ejector according to the presentinvention is less advantageous, because when the driving liquid issupplied in the manner according to the present invention the cost ofworking the pump is considerably increased At low heights of deliverythe amount of work to be done is, however, too small in relation to the'cost of the hydraulic improvement to be made to pay. The circumstancesare different when greater delivery heights, amounting, for instance toseveral hundreds of metres, are required, because, in this case, thedegree of efficiency of the pump assumes far greater importance. Whendelivery heights of about one thousand metres and more are involved thepump efficiency exerts an absolutely decisive influence.

Within the sphere of usefulness of the ejector pump according to thepresent invention there comes, for example, the feeding of high pressurevessels with a pasty mixture of finegrained contact substance and heavyoil for the synthetic production of benzine. For this purpose theejector is driven withpreheated oil under pressure, which oil is to besubjected to hydrogenation. In the vmore recent processes in thechemical industry which are worked at high pressures and in most caseswith a pulverulent contact substance, there are other spheres ofusefulness which are substantially similar to those for the productionof light oil. A particularly wide range of application of the processaccording to this invention is, however, the raising of oil from verydeep bore holes. When the invention is used for this purpose it isadvantageous to arrange the supply of the driving liquid to accord withto the extension of the pipe. 7

An ejector apparatus suitable for this purpose is diagrammatically shownin the drawing in section along the longitudinal axis.

This apparatus comprises a pipe 1 for the pressure liquid and a pipe 2for the liquid to be raised. The mixture of the pressure liquid underwhich the liquid to be raised is effected b means of ejector nozzles 3,4, 5, 6, 7 and 8. T e part of the apparatus worked by the nozzles 7 and8 has a particularly advantageous action, because a retardation of theflow of the liquid through the apparatus is obtained in front of each ofthese nozzles by an enlarged part of the pipe 2 and consequently anincrease of'pressure is produced. This increase of pressure may beobtained with' a suitably modified construction, for example, by an eddyflow (c wr=a constant) of the liquid. This advantageous gain in pressureby the retardation of the flow of the liquid may obviously be extendedto. the whole of the ejector apparatus with the exception of the part infront of the first nozzle 3. In addition to this the several pressurenozzles may be arranged at any desired? distance apart determined assuitable by the local conditions. WVhen the apparatus is built into abore hole the advantage secured thereby is that only a fractional partof the driving liquid needs to be taken down to the lowest point of theconveying pipe, the remaining portion being tapped oll' at. lesserdepths from the pressure pipe. This arrangen'ieut of the ejector nozzlesdistributed over the whole depth of the bore hole naturally results in areduction of the necessary cross sections and an economy in pipe losses.

\Vhat I claim is 1. The method of creating a high liquid pressure in aconduit which comprises admitting a liquid under low pressure into theconduit, and successively imparting to it, during its passage throughthe conduit. increments of pressure totaling the dill'erential betweensaid high and low pressures by impulses from individual jets from asingle column of a liquid under a pressure less than the said highpressure to be created.

2. The method of creating a high liquid pressure in a conduit which.comprises admitting a liquid under low pressure into' the cond' t, andsuccessively imparting to it, during its passage through the conduit,impulses from individual jets of a pressure liquid which is under apressure such that the difference of pressure between the inlet andoutlet of the pressure liquid to and from the conduit is less than thehigh pressure to be created.

In testimony whereof, I have alfixed my signature.

PAUL SCHMIDT.

